Updated October 24, 2026
You can't open a DICOMDIR file by itself, because it holds no images — it is a list of where the images are. Choose the disc, or the folder that contains DICOMDIR, with Open a disc or folder… above. MesDICOM reads the image files themselves and opens your study.
What is a DICOMDIR file?
DICOMDIR is the index the DICOM standard puts at the top of a disc or USB drive. It lists the patients, studies, series and images on the media and where each image file sits. The images are separate files, usually in a folder named DICOM, often with names like IM000001 and no extension.
That is why opening DICOMDIR in a viewer that expects images shows nothing, or an error: there are no pixels in it.
How do I open a disc that has a DICOMDIR?
- Insert the disc or USB drive. If a viewer program starts, close it.
- Click Open a disc or folder… and choose the drive itself, or the folder that holds DICOMDIR.
- MesDICOM reads every file, keeps the DICOM images, and sorts them into studies and series.
If the disc holds more than one study, you choose which to open. The full walk-through, including what to do when the browser won't offer the drive, is in opening a CT or MRI disc.
What happens if I pick only DICOMDIR?
MesDICOM recognises it and says so: this is the disc's index, not the images. It offers Open a disc or folder… so you can choose the folder that holds DICOMDIR, and the images come with it.
Does it work with a copy of the disc?
Yes. A copy on your computer, a USB stick or a shared drive opens the same way, as long as you copy the whole disc — the image folders matter, DICOMDIR itself is optional. A ZIP of the disc opens too, with Open files or a ZIP….
Which images open?
CT, MR, X-ray, ultrasound and other DICOM images, single images and multi-frame series, in the common uncompressed and compressed formats (JPEG, JPEG Lossless, JPEG-LS, JPEG 2000 and RLE).
MesDICOM shows the images; it doesn't interpret them.
